JPH035382Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cutter used for cutting a parallel corrugated metal pipe as an outer conductor of a coaxial cable.

Recently, there has been an increasing demand for cutters that can easily process the ends of parallel corrugated metal pipes as outer conductors of coaxial cables, have little variation during processing, and do not cause deterioration in cable performance. When cutting parallel corrugated metal pipes like this, it is necessary to cut the crests of the pipe due to the connection structure with fittings, etc., but with conventional cutters like those shown in Figures 1 and 2, the crests of the pipe cannot be cut accurately. It is difficult to cut into pieces.

In other words, in the cutters shown in Figures 1 and 2, the guide roll 1
is formed into a cylindrical shape, the guide roll 1 and cutting blade 2 shift in the axial direction as shown by the imaginary line in FIG.
It is difficult to cut.

Another conventional example is to form the cross-sectional shape of the guide roll into a convex shape along the pipe valley.
Cutters have also been developed in which the guide rolls are in contact with the troughs, but if the rolls are in contact with the troughs, not only will a sufficient contact area not be obtained in the troughs with a small diameter, but the guide rolls will be in contact with the troughs. As the diameter of the roll increases, the bending moment that distorts the shaft of the guide roll also increases. As a result, the guide rolls no longer perform a sufficient guiding function, causing the cutting blade to become misaligned, making it impossible to accurately cut the pipe. In addition, as shown in Figure 5, the water-shielding coaxial cable has a parallel corrugated metal pipe P as the outer conductor.
A foamed insulator T and a center conductor C are built into the pipe P, and by digging the valley R of the pipe P into the insulator T, it exerts a water-blocking function, and also prevents the valley R from entering the insulator T. Good electrical characteristics are maintained by keeping the biting amount constant. However, if distortion occurs in the valleys R, the valleys R may come off from the insulator T, impairing the water-blocking function, or the amount of penetration of the valleys R may vary, impairing electrical characteristics.

The purpose of this invention is to improve the stability of the guiding function of the guide rolls, to be able to accurately cut the peaks of parallel corrugated metal pipes, to prevent performance deterioration of coaxial cables, and to make the guide rolls themselves more compact. The gist is that the cutter body is equipped with a plurality of guide rolls that move around the outer circumference of the parallel corrugated metal pipe together with the body.
A cutter for a parallel corrugated metal pipe as an outer conductor of a coaxial cable, which is equipped with a cutting blade, has a cross-sectional shape that follows the shape of the crest of the pipe, and has a cutter that is attached to each crest that is separated by two or more pitches so that it cannot move in the axial direction. A guide roll is constituted by a pair of guide parts that are in contact with each other and a shaft part that rotatably supports the pair of guide parts on the cutter body, and the cutting blade is provided so as to come into contact with the peak of the pipe peak or near the peak. That's what happened. The present invention will be explained below based on the drawings.

In FIG. 3, reference numeral 11 denotes a cutter body that is generally C-shaped and has a cylindrical handle 12 at one end. P-side inner peripheral surface 13 of the pipe of the handle 12 (parallel corrugated metal pipe as the outer conductor of the coaxial cable)
is formed into a quadrilateral cross-sectional shape, and a cutting blade support rod 15 is inserted into the quadrilateral inner circumferential surface 13 so as to be movable in the length direction of the handle 12 but not rotatable.
The cross-sectional shape of the rod 15 is quadrilateral. Rod 1
A disc-shaped cutting blade 17 is rotatably supported at the end of the pipe P side of the pipe 5 via a pin 16. A female threaded hole 19 is formed in the portion of the rod 15 opposite to the cutting blade, and a cutting blade moving (pressing) bolt 20 is screwed into this female threaded hole 19. The bolt 20 extends to the outside of the handle 12, and has a handle 2 at the tip.
1 is fixed by a set bolt 22. The bolt end side portion 20a is rotatably supported by a stopper cylindrical metal fitting 23, and the metal fitting 23 is screwed onto the end of the handle portion 12 on the side opposite to the pipe P. Further, a flange-shaped stopper portion 20b is formed in a portion inside the handle portion 12 of the bolt 20, and the stopper portion 20b is in contact with the end surface of the metal fitting 23 on the pipe P side. That is, the bolt 2 for moving the cutting blade is connected by the metal fitting 23.
0 is supported rotatably but immovably in the axial direction. Therefore, by rotating the handle 21 in one direction, the cutting blade 17 moves toward the pipe center O, and by rotating the handle 21 in the other direction, it moves away from the pipe center O.
Move to the side.

A bifurcated holder 25 is provided at the end of the main body 11 on the side opposite to the handle 12. A boss portion 26 is formed at each tip of the holder 25, and a guide roll 27 is provided on each boss portion 26 to rotate. It is freely supported. Both guide rolls 27 have their center lines aligned with the pipe center line O.
They are arranged parallel to the pipe P and spaced apart from each other in the circumferential direction of the pipe P. Both rolls 27 and the cutting blade 17 are approximately located at each vertex of an equilateral triangle.

In FIG. 4, which is an enlarged cross-sectional view of FIG. It's summery. The outer circumferential cross-sectional shape of the guide parts 29, 29' is the pipe ridge part Q ₁ , Q ₃
For example, the guide portion 29 is formed in a 1/4 arc shape, and the 1/4 arc surface 29a of the right guide portion 29 in FIG. and guide part 2 on the left side in Fig. 4.
The 1/4 arcuate surface 29a' of the guide portion 29' is formed such that the diameter of the guide portion 29' decreases toward the left side.
Both guide portions 29, 29' have arcuate surfaces 29a, _29a and 29a, respectively, on the peaks Q1 and _Q3 , which are spaced apart by two pitches, for example.
29'a are spaced apart so that they fit into each other. Further, the cutting blade 17 is arranged so as to come into contact with the apex of the pipe crest Q ₂ between the guide parts 29 and 29'.

When cutting a parallel corrugated metal pipe P, first widen the distance between the guide roll 27 and the cutting blade 17 by turning the handle 21.
Insert between 7. And both guide parts 29, 29'
are in contact with the peaks Q ₁ and Q ₃ that are 2 pitches apart, respectively,
By turning the handle 21, the cutting blade 17 is pressed to the extent that it bites into the top of the peak _Q2 between the guide parts 29, 29'. After that, the cutter body 11 is rotated around the center O of the pipe P in the direction of arrow A (or opposite arrow A) in FIG. do.

Note that the axial distance between the guide portions 29 and 29' is as follows:
The spacing may be such that they can abut the pipe peaks that are 4 or 6 pitches apart or more apart.
In addition, a jack-like structure is used so that the axial distance between the two guide parts 29, 29' is evenly spread to the left and right in FIG. It may be pressed in the axial direction on the portions Q ₁ and Q ₃ .

Further, the cutting blade 17 may be brought into contact with the peak Q ₁ or Q ₃ in FIG. 4.

Further, as a modification of the guide portions 29, 29', the outer circumferential surface may be formed to have a circular cross-sectional shape.

As explained above, the present invention has a cutter main body 11.
, a plurality of guide rolls 27 that rotate around the outer periphery of the parallel corrugated metal pipe P together with the main body 11, and a cutting blade 1.
_{In the} parallel corrugated metal pipe _{cutter with} A guide roll 27 is constituted by a pair of guide parts 29, 29' that abut against each other in a direction that cannot be moved, and a shaft part 28 that rotatably supports these guide parts 29, 29' on the cutter body 11. Since it is provided so as to be in contact with the apex of the mountain portion Q or near the apex, there are the following advantages.

(1) Pipe peaks Q ₁ and Q ₃ that are more than 2 pitches apart are 1
Since the pair of guide parts 29 and 29' guide the cutting blade 1, the guiding function is stable.
There is no need to worry about the position of 7 shifting, and the pipe P can be cut with high precision.

(2) Since the crests Q ₁ and Q ₃ are guided and the ridges Q ₂ are cut, the trough R (fourth
There is no need to worry about distortion occurring in the image (see figure). Therefore, it is particularly suitable as a pipe cutter for water-shielding high-frequency coaxial cables. In other words, the water-shielding coaxial cable is the fifth
As shown in the figure, a foamed insulator T and a center conductor C are built into a metal pipe P with parallel waves as an external conductor, and the valley R of the pipe P is cut into the insulator T to provide insulation. It exhibits a water function and also maintains good electrical characteristics by keeping the amount of penetration of the valley R into the insulator T constant. However, if distortion occurs in the valleys R, the valleys R may come off from the insulator T, impairing the water-blocking function, or the amount of penetration of the valleys R may vary, impairing electrical characteristics. According to the present invention, there is no concern that distortion will occur in the valley R, so there will be no adverse effect on the water-shielding properties and electrical characteristics of the water-shielding high-frequency coaxial cable.

(3) Since Yamabe Q ₁ and Q ₃ are arranged as guides,
By reducing the diameter of the guide portions 29, 29', the moment exerting distortion on the guide roll shaft is reduced, and not only the looseness of the guide roll 27 is reduced, but also the guide roll 27 can be made compact.

(4) Since the terminal cuts at or near the apex of the peak Q ₂ and utilizes the expansion of the peak as it is, the terminal processing (of the cut surface) with stable strength over a long period of time is possible without undue straightening. Furthermore, the work of connecting connectors in coaxial cables (FIG. 5) and the like can be easily performed.

(5) Not only the terminal processing (cutting processing) work but also the structure of the connector can be simplified and the cost can be reduced.

In addition, in the present invention, three or more guide rolls 27 may be provided.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the conventional example, Fig. 2 is an enlarged view of Fig. 1 in the direction of the arrow, Fig. 3 is a partially vertical side view of the cutter according to the present invention, and Fig. 4 is an enlarged cross-sectional view of Fig. 3. , FIG. 5 is a longitudinal sectional view showing an example of a parallel corrugated metal pipe. 11...Katsuta body, 17...Incision blade, 27...
...Guide roll, 28...Shaft portion, 29, 29'...
...Guide department.

Claims (1)

[Scope of utility model registration request] In a cutter for a parallel corrugated metal pipe as an outer conductor of a coaxial cable, the cutter body is equipped with a plurality of guide rolls that rotate around the outer periphery of the parallel corrugated metal pipe together with the main body, and a cutting blade. a pair of guide parts each having a cross-sectional shape along the shape of the cutter and abutting each mountain part separated by two or more pitches in an axially immovable manner, and a shaft part rotatably supporting the pair of guide parts on the cutter body. 1. A cutter for a metal pipe with parallel waves as an outer conductor of a coaxial cable, characterized in that a guide roll is constituted by the above, and a cutting blade is provided so as to come into contact with the apex or near the apex of the pipe crest.